Liquid crystal display device

ABSTRACT

An IPS-method liquid crystal display device which exhibits small directivity of a viewing angle and high brightness is realized. A planar common electrode is arranged below a pixel electrode which includes comb-teeth-shaped electrodes and slits. When a video signal is applied to the pixel electrode, an electric field is generated between the pixel electrode and the common electrode by way of slit portions formed in the pixel electrode thus controlling liquid crystal molecules. To reduce the occurrence of a phenomenon that an abnormal domain is generated in an end portion of the slit and the abnormal domain lowers transmissivity of liquid crystal, the structure in which the slits having both ends thereof closed and the slits having one-side end portion thereof opened are alternately arranged next to each other in parallel is adopted.

The present application claims priority from Japanese applicationJP2007-299271 filed on Nov. 19, 2007, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device, andmore particularly to a lateral-electric-field liquid crystal displaydevice which exhibits excellent viewing angle characteristic andbrightness characteristic.

2. Background Art

A liquid crystal display device includes a TFT substrate on which pixelelectrodes, thin film transistors (TFT) and the like are formed in amatrix array and a counter substrate which forms color filters or thelike thereon at places where the color filters faces the pixelelectrodes in an opposed manner, and liquid crystal is sandwichedbetween the TFT substrate and the counter substrate. Further, an imageis formed by controlling transmissivity of light for every pixel bydriving liquid crystal molecules.

A viewing angle characteristic is critically important in the liquidcrystal display device. The viewing angle characteristic is a phenomenonthat brightness is changed or chromaticity is changed between a casewhere a screen is observed from a front side and a case where the screenis observed in the oblique direction. With respect to the viewing anglecharacteristic, an IPS (In Plane Switching)-liquid crystal displaydevice which operates liquid crystal molecules using an electric fieldwhich contains at least electric-field components in the horizontaldirection exhibits excellent viewing angle characteristic.

Although the IPS-method liquid crystal display device exhibits anexcellent viewing angle characteristic, pixel electrodes and commonelectrodes (also referred to as counter electrodes) are formed on thesame substrate, that is, on a TFT substrate and hence, the IPS-methodliquid crystal display device has a drawback that a so-called TN-methodliquid crystal display device in which pixel electrodes are formed on aTFT substrate and counter electrodes are formed on a counter substratedoes not have.

The constitution of the IPS-method liquid crystal display device hasvarious modes. In the constitution of one mode, the pixel electrode andthe counter electrode are respectively formed into a comb-teeth shape,and the pixel electrode and the counter electrode are alternatelyarranged next to each other in parallel. In this constitution, distalends of the comb-teeth are set as open ends and, at the same time, openends of the comb teeth of the pixel electrode and open ends of the combteeth of the counter electrode are arranged on the same side and hence,the open ends of the comb teeth are easily influenced by a potential ofother electrodes or lines. Particularly, when a scanning line isarranged adjacent to the open end of the comb teeth, the open end of thecomb teeth is easily influenced by the potential of the scanning line.

JP-A-2000-292802 (patent document 1) discloses the constitution whichprevents the influence of a potential of a scanning line fromimpregnating a region where liquid crystal within a comb teeth iscontrolled by increasing widths of open ends of comb-teeth-shapedelectrodes of pixel electrodes and common electrodes.

Although the IPS-method liquid crystal display device possesses anexcellent viewing angle characteristic compared with a liquid crystaldisplay device adopting other liquid crystal driving method, the viewingangle characteristic of the IPS-method liquid crystal display device isless than optimal. For example, a hue is delicately changed between acase where a screen is observed from one direction and a case where thescreen is observed in another direction. Although this change of hue isvery small compared to a change of hue in a liquid crystal displaydevice adopting other liquid crystal driving method, there still existsa space for improvement.

JP-A-2003-280017 (patent document 2) discloses the constitution whichreduces the directivity of a viewing angle in such a manner thatcomb-teeth-shaped pixel electrodes and comb-teeth-shaped commonelectrodes are bent in a chevron shape within one pixel, and therotational direction of the liquid crystal is set in two directionswithin one pixel. However, by bending the pixel electrodes or the likein a chevron shape, particularly in a proximal portion of the combteeth, an abnormal electric field is generated thus forming places whereliquid crystal cannot be controlled. Patent document 2 discloses theconstitution which improves a shape of the electrode in the proximal endof the comb teeth of the pixel electrode or the like thus reducing suchan abnormal electric field leading to the suppression of the decrease oftransmissivity.

Other drawback of the IPS-method liquid crystal display device lies inthat the pixel electrodes and the common electrodes are formed on thesame substrate, that is, on the TFT substrate and hence, transmissivityof light from a backlight is lowered. That is, in the so-calledTN-method liquid crystal display device or the like, although the pixelelectrodes are formed on the TFT substrate, the common electrodes areformed on the counter substrate. Accordingly, the TN-method liquidcrystal display device can reduce an area where light is blocked by theelectrodes compared to the IPS-method liquid crystal display device.

To overcome such a drawback, there has been proposed a followingIPS-method liquid crystal display device. That is, pixel electrodes andcommon electrodes are formed on different layers, the pixel electrodehas comb-teeth-shaped electrodes and slits, and a common electrode isformed of a planar electrode. The comb-teeth-shaped electrode has adistal ends thereof closed, and liquid crystal molecules are controlledby the electric field generated between the comb-teeth-shaped electrodesand common electrodes thus forming an image. By forming the pixelelectrodes and the common electrodes using a transparent electrode,transmissivity of the liquid crystal display device is largely enhancedthus enabling the acquisition of transmissivity sufficiently comparativeto the transmissivity of the liquid crystal display device of TN-methodor the like.

Due to such constitution, this IPS-method liquid crystal display devicecan largely enhance the transmissivity compared to the conventionalIPS-method liquid crystal display device. However, there still exists aspace for improvement with respect to this IPS-method liquid crystaldisplay device. That is, at the distal end of the comb teeth which isclosed, there arises a phenomenon in which a region where the liquidcrystal cannot be controlled is formed and the transmissivity is loweredin such a portion.

Y. B. Lee, et al. IDW'06 LCT5-4, P627-630 (non-patent document 1), forovercoming such a drawback, discloses the constitution which isconfigured to prevent the decrease of transmissivity by forming allslits formed in a pixel electrode into open ends and by forming acomb-teeth shape into a shape such as legs of a crab.

SUMMARY OF THE INVENTION

The object of the present invention lies in the further improvement oftransmissivity in an IPS-method liquid crystal display device in whichpixel electrodes formed of a transparent electrode and common electrodesformed of a transparent electrode are formed on different layers, thepixel electrodes 110 are formed in a comb-teeth shape, and the commonelectrodes are formed of a planar electrode. One example of the pixelelectrode of the IPS-method liquid crystal display device having suchconstitution is shown in FIG. 17.

In FIG. 17, a pixel is formed in a laterally-extending trapezoidalshape. Slits 112 are formed in the trapezoidal pixel. Acomb-teeth-shaped electrode 1101 is formed between this slit 112 and aslit arranged adjacent to the former slit 112. An electric fielddirected in a particular direction is generated in an end portion of theslit 112, that is, in a region A shown in FIG. 17, and a phenomenon thatliquid crystal molecules 113 are not moved even when a video signal isapplied to a pixel electrode 110 arises. Accordingly, the transmissivityof the liquid crystal display device is decreased by an amountcorresponding to the region A.

Non-patent document 1 discloses the constitution which is configured toprevent the decrease of transmissivity in the region A by making lateralends of the comb-teeth-shaped electrodes alternately open ended, thatis, by making the comb-teeth-shaped electrodes into one meanderinglinear electrode and, at the same time, by forming a shape of thecomb-teeth shape into a crab leg shape. However, in the constitutiondisclosed in non-patent document 1, only the single electrode is usedand hence, there is a large possibility of the disconnection of thepixel electrode. Further, the formation of the pixel electrode into acrab-leg shape makes the shape of the pixel electrode complicated thuslowering a manufacturing yield ratio. Further, there arises a phenomenonthat transmissivity is not enhanced to an expected level at acrab-leg-shaped portion.

It is an object of the present invention to provide an IPS-method liquidcrystal display device which can enhance transmissivity whilemaintaining reliability of the liquid crystal display device against thedisconnection of pixel electrodes and, at the same time, preventinglowering of a manufacturing yield ratio.

The present invention is provided for overcoming the above-mentioneddrawbacks, and is characterized in that in a pixel electrode havingslits and comb-teeth-shaped electrode, the slits having both endsthereof closed and the slits having only one-side end portions thereofopened are alternately arranged next to each other in parallel.Alternatively, the present invention is characterized in that thecomb-teeth-shaped electrodes are cut-off portion at end portions of theslits. To explain specific means of the present invention, they are asfollows.

(1) According to a first aspect of the present invention, there isprovided a liquid crystal display device which includes: a TFTsubstrate; a counter substrate; and liquid crystal which is sandwichedbetween the TFT substrate and the counter substrate, wherein the TFTsubstrate includes planar first electrodes, an insulation film whichcovers the first electrodes, and second electrodes which are formed onthe insulation film in an overlapping manner with the first electrodes,the second electrode includes slits and comb-teeth-shaped electrodes,the liquid crystal is configured to be driven by an electric fieldgenerated due to potential difference between the first electrode andthe second electrode, and the slits are configured such that the slitshaving both ends thereof closed and the slits having only one-side endportion thereof opened are alternately arranged next to each other inparallel.

(2) In the liquid crystal display device having the constitution (1),within one pixel, the slits having only one-side end portions thereofopened are configured such that the slit opened on one end portion sideand the slit opened on another end portion side are arranged alternatelyby way of the slit having both end portions thereof closed.

(3) In the liquid crystal display device having the constitution (1),within one pixel, the slits having said only one-side end portionsthereof opened include the slits opened on one end portion side and theslits opened on another end portion side.

(4) In the liquid crystal display device having the constitution (1),within one pixel, the slits having said only one-side end portionsthereof opened are opened only on the same one end portion siderespectively.

(5) According to a second aspect of the present invention, there isprovided a liquid crystal display device which includes: a TFTsubstrate; a counter substrate; and liquid crystal which is sandwichedbetween the TFT substrate and the counter substrate, wherein the TFTsubstrate includes planar first electrodes, an insulation film whichcovers the first electrodes, and second electrodes which are formed onthe insulation film in an overlapping manner with the first electrodes,the second electrode includes slits and comb-teeth-shaped electrodes,the liquid crystal is configured to be driven by an electric fieldgenerated due to potential difference between the first electrode andthe second electrode, and the comb-teeth-shaped electrode is configuredsuch that a cut-off portion which is integrally formed with the slit isformed in one end portion side of comb-teeth-shaped electrode, and saidone end portion side of the comb-teeth-shaped electrode has a widthsmaller than a width of another end portion side of thecomb-teeth-shaped electrode.

(6) In the liquid crystal display device having the constitution (5),the slits are configured such that the slits having both ends thereofclosed and the slits having only one-side end portions thereof openedare alternately arranged next to each other in parallel.

(7) According to a third aspect of the present invention, there isprovided a liquid crystal display device which includes: a TFTsubstrate; a counter substrate; and liquid crystal which is sandwichedbetween the TFT substrate and the counter substrate, wherein the TFTsubstrate includes planar first electrodes, an insulation film whichcovers the first electrodes, and second electrodes which are formed onthe insulation film in an overlapping manner with the first electrode,the second electrode includes slits and comb-teeth-shaped electrodes,the liquid crystal is configured to be driven by an electric fieldgenerated due to potential difference between the first electrode andthe second electrode, and the comb-teeth-shaped electrode includes afirst side and a second side which respectively extend in a longitudinaldirection and face each other in an opposed manner with the slitsandwiched therebetween, a cut-off portion which is integrally formedwith the slit is formed only in one side out of the first side and thesecond side on at least one end portion of the comb-teeth-shapedelectrode, and another side out of the first side and the second side isformed in a straight line without being bent.

(8) In the liquid crystal display device having the constitution (7),the cut-off portion which is integrally formed with the slit only on oneside is formed in both end portions of the comb-teeth-shaped electrode.

(9) In the liquid crystal display device having the constitution (7),the cut-off portion which is integrally formed with the slit only on oneside is formed in only one end portion of the comb-teeth-shapedelectrode.

According to the present invention, in the IPS-method liquid crystaldisplay device which includes the TFT substrate on which the pixelelectrodes having the comb-teeth-shaped electrode and the slits and theplanar common electrode are formed in an overlapping manner by way ofthe insulation film, an abnormal domain in the slit end portion, thatis, a region where control of liquid crystals in response to a videosignal applied to the pixels is not possible can be decreased and hence,transmissivity of the liquid crystal display device can be enhanced thusrealizing the acquisition of a liquid crystal display device whichexhibits high brightness.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a liquid crystal display device towhich the present invention is applied;

FIG. 2 is a view of the arrangement of pixels of an embodiment 1;

FIG. 3 is an enlarged view of a pixel electrode of the embodiment 1;

FIG. 4 is a view showing another example of the pixel electrode of theembodiment 1;

FIG. 5 is a view showing still another example of the pixel electrode ofthe embodiment 1;

FIG. 6 is a view showing still another example of the pixel electrode ofthe embodiment 1;

FIG. 7 is a view showing a TFT portion of the embodiment 1 in asee-through manner;

FIG. 8 is a plan view of a counter substrate as viewed from a TFTsubstrate side;

FIG. 9 is a view of the arrangement of pixels according to anothermodification of the embodiment 1;

FIG. 10 is a view of the arrangement of pixels of an embodiment 2;

FIG. 11 is an enlarged view of a pixel electrode of the embodiment 2;

FIG. 12 is an enlarged view of a distal end portion of acomb-teeth-shaped electrode of the embodiment 2;

FIG. 13 is an enlarged view of the pixel electrodes according to anothermodification of the embodiment 2;

FIG. 14 is an enlarged view of the pixel electrodes according to stillanother modification of the embodiment 2;

FIG. 15 is an enlarged view of the pixel electrodes according to stillanother modification of the embodiment 2;

FIG. 16 is an enlarged view of a pixel electrode of an embodiment 3; and

FIG. 17 is a view showing an example of a pixel electrode to which thepresent invention is not applied.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Prior to the explanation of specific embodiments of the presentinvention, the structure of an IPS-method liquid crystal display device(hereinafter, referred to as an IPS) to which the present invention isapplied is explained. FIG. 1 is a cross-sectional view of the vicinityof a TFT of the IPS to which the present invention is applied. In FIG.1, on a TFT substrate 100 made of glass, gate electrodes 101 are formed.The gate electrodes 101 are formed on the same layer with scanning lines1011. The gate electrode 101 is formed by stacking an MoCr alloy layeron an AlNd alloy layer.

A gate insulation film 102 made of SiN is formed so as to cover the gateelectrodes 101. On the gate insulation film 102, semiconductor layers103 made of a-Si are formed at positions where the semiconductor layers103 face the gate electrodes 101 in an opposed manner. The semiconductorlayers 103 made of a-Si are formed by a plasma CVD method. A sourceelectrode 104 and a drain electrode 105 are formed on the a-Si layerwhich forms a channel portion of a TFT. The source electrode 104 alsofunctions as a video signal line, and the drain electrode 105 isconnected with a pixel electrode 110. Both of the source electrode 104and the drain electrode 105 are formed on the same layer simultaneously.In this embodiment, the source electrode 104 or the drain electrode 105is made of MoCr alloy. When it is necessary to lower the electricresistance of the source electrode 104 or the drain electrode 105, forexample, the electrode structure which sandwiches an AlNd alloy layerbetween MoCr alloy layers is used.

An inorganic passivation film (insulation film) 106 is formed of aninorganic insulation film made of SiN or the like so as to cover theTFTs. The inorganic passivation film 106 particularly protects thechannel portions of the TFTs from impurities. On the inorganicpassivation film 106, an organic passivation film (insulation film) 107is formed. The organic passivation film 107 also plays a role ofleveling a surface of the TFT besides a role of protecting the TFT andhence, the organic passivation film 107 has a large thickness. Thethickness of the organic passivation film 107 is set to a value whichfalls within a range from 1 μm to 4 μm.

The organic passivation film 107 is made of a photosensitive acrylicresin, silicon resin, polyimide resin or the like. It is necessary toform through holes in the organic passivation film 107 at positionswhere the pixel electrodes 110 and the drain electrodes 105 areconnected with each other. Since the organic passivation film 107 isformed of a photosensitive film, it is possible to form the throughholes in the organic passivation film 107 by exposing and developing theorganic passivation film 107 per se without using a photoresist.

A common electrode (counter electrode) 108 is formed on the organicpassivation film 107. The common electrode 108 is formed of an ITO(Indium Tin Oxide) film which is a transparent conductive film and isformed on the whole display region by sputtering. That is, the commonelectrode 108 is formed into a planar shape. After forming the commonelectrode 108 on the whole surface of the display region by sputtering,the common electrode 108 is removed by etching at only through-holeportions which are necessary for making the pixel electrode 110 and thedrain electrode 105 conductive with each other.

An upper insulation film 109 made of SiN is formed so as to cover thecommon electrode 108. After forming the upper insulation film 109,through holes are formed in the upper insulation film 109 by etching.Using the upper insulation film 109 as a resist, the through holes 111are formed by etching the inorganic passivation film 106. Thereafter, atransparent conductive film made of ITO which becomes pixel electrodes110 later is formed by sputtering so as to cover the upper insulationfilm 109 and the through holes 111. The pixel electrodes 110 are formedby patterning the ITO film which is formed by sputtering. The ITO filmwhich forms the pixel electrodes 110 is also formed on the through holes111. In the through hole 111, the drain electrode 105 which extends fromthe TFT and the pixel electrode 110 are made conductive with each otherso that a video signal is supplied to the pixel electrode 110.

As described later, the pixel electrode 110 is formed of acomb-teeth-shaped electrode with both ends closed. A slit 112 is formedbetween the comb-teeth-shaped electrodes. A predetermined potential(also referred to as a reference potential or a common potential) isapplied to the common electrode 108 and a potential corresponding to avideo signal is applied to the pixel electrodes 110. As shown in FIG. 1,when a potential is applied to the pixel electrode 110, lines ofelectric force are generated and liquid crystal molecules 113 arerotated in the direction of the lines of electric force thus controllingthe transmission of light from a backlight. That is, by making use of anelectric field generated due to potential difference between the commonelectrode 108 and the pixel electrode 110, the liquid crystal molecules113 are driven. Since the transmission of light from the backlight canbe controlled for every pixel, it is possible to form an image. Here,although an alignment film for aligning the liquid crystal molecules 113is formed on the pixel electrode 110, the alignment film is omitted fromFIG. 1.

In an embodiment explained hereinafter, the explanation is made assumingthat the common electrode 108 which is formed into a planar shape isarranged on the organic passivation film 107, and the pixel electrodes110 having comb-teeth-shaped electrodes 1101 are arranged on the upperinsulation film 109. However, opposite to such an arrangement, thepresent invention is also applicable to a case where thepixel-electrodes 110 which are formed into a planar shape are arrangedon the organic passivation film 107 and a comb-teeth-shaped commonelectrode 108 is arranged on the upper insulation film 109 in the samemanner as the above-mentioned constitution.

Embodiment 1

FIG. 2 is a plan view showing the arrangement of the pixels on the TFTsubstrate 100 of the embodiment 1. FIG. 3 is an enlarged view of a pixelAA shown in FIG. 2. FIG. 6 is an enlarged view of a pixel BB shown inFIG. 2. The pixel AA and the pixel BB are arranged in symmetry. FIG. 7is an enlarged view showing a portion B shown in FIG. 2 in a see-throughmanner.

In FIG. 2, to prevent the drawing from becoming complicated, only thepixel electrodes 110 and the scanning line 1011 are shown. In FIG. 2,the pixel is formed in a laterally-extending trapezoidal shape.Conventionally, the pixel is defined by a region surrounded by videosignal lines 1041 and scanning lines 1011. However, in this embodiment,the pixel is defined by the pixel electrode 110 per se. Further, thepixels are arranged in the longitudinal direction such that the pixel AAand the pixel BB are formed continuously thus providing the packedstructure. Further, the pixels are also arranged in the lateraldirection such that the pixel AA and the pixel BB are formedcontinuously thus providing the packed structure.

Upper and lower boundaries of the pixel in the longitudinal directionare defined neither by the scanning lines nor by the capacitive lines.That is, the light blocking films are not present on the upper and lowerboundaries of the pixel. Accordingly, upper and lower ends of the pixelcan be also used for forming the image and hence, the transmissivity canbe increased whereby a liquid crystal display device having highbrightness can be realized.

As shown in FIG. 2, a profile of each pixel is formed in alaterally-extending trapezoidal shape. In FIG. 2, slits 112 are formedalong sides of the trapezoidal shape. In other words, thecomb-teeth-shaped electrodes 1101 are formed with the same inclinationas the sides of the trapezoidal shape. Accordingly, the inclination ofthe pixel electrode 110 becomes opposite to each other between an upperhalf region and a lower half region of the pixel electrode 110. Due tosuch constitution, as explained hereinafter, it is possible to eliminatethe directivity of a viewing angle.

When a potential corresponding to a video signal is applied to the pixelelectrode 110, as explained in conjunction with FIG. 1, lines ofelectric force is generated from the pixel electrode 110 to the planarcommon electrode 108 arranged below the pixel electrode 110 through theslit 112 and via the upper insulation film 109, and liquid crystal isrotated along the lines of electric force and hence, light from abacklight which passes through the pixel is controlled thus forming animage.

In this embodiment, the direction of alignment axis of liquid crystal isthe lateral direction as indicated by an arrow AL in FIG. 2. When apotential corresponding to a video signal is applied to the pixelelectrode 110, since the direction of the comb-teeth-shaped pixelelectrode 110 is opposite to each other, the rotational direction ofliquid crystal differs from each other between an upper side and a lowerside of the pixel electrode 110. Accordingly compared to a case in whichthe liquid crystal molecules 113 are rotated only in a specifieddirection, it is possible to reduce the directivity of viewing angle.

On the other hand, between the upper portion and the lower portion ofthe pixel, the inclination of the comb-teeth-shaped electrode 1101 isopposite to each other and hence, a region which does not contribute tothe formation of an image is formed at the center of the pixel in thelongitudinal direction. In this embodiment, by extending the scanningline 1011 over this portion, the reduction of transmissivity isprevented as the whole pixel. In this embodiment, the scanning line 1011extends linearly in the lateral direction.

FIG. 3 is an enlarged view of the pixel electrode 110 of the pixel AA inFIG. 2. FIG. 3 shows only the pixel electrode 110. In FIG. 3, the slits112 of the pixel electrode 110 have end portions thereof opened forevery one other slit (at a rate of one slit for every two slits). Thatis, the slit 112 having both ends thereof closed and the slit 112 havingonly one-side end portion thereof opened are alternately arranged nextto each other in parallel. However, the opened end portions of the slits112 are formed alternately on different sides of the trapezoidal pixelelectrode 110. Accordingly, within one pixel electrode 110, allcomb-teeth-shaped electrodes 1101 are made conductive with each other.In a portion where a distal end is opened, there is no possibility thata region where liquid crystal cannot be controlled due to a potential ofthe pixel electrode 110 caused by a peculiar electric field (hereinafterreferred to as an abnormal domain) occurs. Accordingly, thetransmissivity of the pixel can be enhanced correspondingly.

The constitution that one end of the slit 112 is opened implies that anelectric field generated by the comb-teeth-shaped electrodes 1101 iseasily influenced by other electrode or a phenomenon referred to as aso-called pushed domain which occurs when the liquid crystal displaydevice is pushed from the outside is liable to easily occur. However,the number of opened portions of the slits 112 on one side of the pixelelectrode 110 is one for every four slits and hence, the influence ofother electrode or the so-called pushed domain is extremely small.

On the other hand, in FIG. 3, four comb-teeth-shaped electrodes 1101have one ends thereof connected in common and hence, even when thedisconnection occurs at one of these comb-teeth-shaped electrodes 1101,it is possible to eliminate a case that a video signal is not suppliedto the pixel electrode 110. This structure is extremely important toensure the reliability of the pixel electrode 110.

FIG. 4 shows a modification of the pixel electrode 110 shown in FIG. 3.In FIG. 4, all of the pixel electrodes 110 are connected with each otheron a left side of the pixel electrode 110, while opened portions of thecomb-teeth-shaped electrodes 1101 (slits 112) and closed portions of thecomb-teeth-shaped electrodes 1101 (slits 112) are alternately formed ona right side of the pixel electrode 110. FIG. 5 shows anothermodification of the pixel electrode 110 shown in FIG. 3. In FIG. 5, allof the pixel electrodes 110 are connected with each other on a rightside of the pixel electrode 110, while opened portions of thecomb-teeth-shaped electrodes 1101 (slits 112) and closed portions of thecomb-teeth-shaped electrodes 1101 (slits 112) are alternately formed ona left side of the pixel electrode 110. The example shown in FIG. 4 andthe example shown in FIG. 5 also acquire advantageous effectssubstantially equal to the advantageous effects shown in FIG. 3.

FIG. 6 is an enlarged view of the pixel electrode 110 of the pixel BB inFIG. 2. FIG. 6 shows only the pixel electrode 110. The pixel electrode110 shown in FIG. 6 has a symmetrical relationship with the pixelelectrode 110 shown in FIG. 3, and acquires an advantageous effectsubstantially equal to the advantageous effect acquired by the pixelelectrode 110 shown in FIG. 3. Further, the reliability of the pixelelectrode 110 against the disconnection is substantially equal to thereliability of the pixel electrode 110 shown in FIG. 3. Here, the pixelelectrode 110 shown in FIG. 6 may be configured such that, in the samemanner as the pixel electrode 110 shown in FIG. 4 or FIG. 5corresponding to the pixel electrode 110 shown in FIG. 3, allcomb-teeth-shaped electrodes 1101 are connected with each other only ona left side or a right side of the comb-teeth-shaped electrode 1101, andopened portions and closed portions of the comb-teeth-shaped electrodes1101 (slits 112) are formed alternately on an opposite side.

As shown in FIG. 3 to FIG. 6, according to this embodiment, it is nomore necessary to make a shape of the pixel electrode 110 complicated.Accordingly, there is no possibility that a manufacturing yield ratio islowered. The gist of the present invention lies in the enhancement oftransmissivity without lowering reliability against the disconnectionand also without lowering the manufacturing yield ratio. Further, due tothe presence of the slits 112 having both ends thereof closed among theslits 112, this embodiment can effectively cope with the pushed domain.

FIG. 7 is an enlarged see-through view of a portion B in FIG. 2. In FIG.7, the gate electrode 101 and the scanning line 1011 are indicated by achained line. A portion of the scanning line 1011 where a width of thescanning line 1011 is enlarged forms the gate electrode 101. Thesemiconductor layer 103 indicated by a dotted line is formed on the gateelectrode 101 by way of the gate insulation film 102 not shown in thedrawing. A shape of the semiconductor layer 103 in FIG. 7 is arectangular shape. The source electrode 104 is arranged on a left sideof the semiconductor layer 103. In this case, the video signal line 1041indicated by hatching also functions as the source electrode 104.

The drain electrode 105 indicated by a dotted line is arranged on aright side of the semiconductor layer 103. The drain electrode 105 facesthe source electrode 104. Although a portion of the drain electrode 105which overlaps with the semiconductor layer 103 has a rectangular shape,a further right extending portion of the drain electrode 105 has apseudo octagonal shape. Such constitution is provided for making thedrain electrode 105 larger than the through hole formed in the organicpassivation film 107. Here, in FIG. 7, for preventing the drawing frombecoming complicated, a shape of the through hole formed in the organicpassivation film 107 and the upper insulation film 109 is not describedin the drawing.

In FIG. 7, a gap C of a portion where the source electrode 104 and thedrain electrode 105 face each other forms a channel portion of the TFT.At an approximately center portion of the drain electrode 105 which isformed in a pseudo octagonal shape, a through hole 111 which is formedin the inorganic passivation film 106 having a pseudo octagonal planarshape is provided. The through hole 111 is formed in the inside of thethrough hole formed in the upper insulation film 109 and the organicpassivation film 107.

On the source electrode 104 or the drain electrode 105, the pixelelectrode 110 is formed by way of the inorganic passivation film 106,the organic passivation film 107, the common electrode 108 and the upperinsulation film 109. Here, the common electrode 108 is formed in aplanar shape except for a portion thereof around the through hole andhence, the common electrode 108 is not shown in FIG. 7.

As shown in FIG. 7, the slit 112 is formed between the comb-teeth-shapedelectrodes 1101. When a potential is applied to the comb-teeth-shapedelectrode 1101, lines of electric force extend toward the lower commonelectrode 108 from the comb-teeth-shaped electrode 1101 through the slit112, and some lines of electric force rotate the liquid crystalmolecules 113 on boundaries of the slit 112 and the comb-teeth-shapedelectrode 1101 thus controlling light from the backlight so as to forman image.

FIG. 8 is a view of the counter substrate 200 corresponding to the TFTsubstrate 100 shown in FIG. 2 as viewed from a TFT substrate 100 side.Although the color filters amounting approximately one pixel in thelongitudinal direction are shown in FIG. 8, in an actual model, the redfilter R, the green filter G and the blue filter B are formed in astripe shape. In the pixel arrangement shown in FIG. 2, the pixels whichdisplay the same color are arranged in the longitudinal direction.Accordingly, it is unnecessary to consider color mixing in thelongitudinal direction.

In FIG. 8, the light blocking films 201 which are formed on the countersubstrate 200 are indicated by a dotted line. The light blocking films201 are formed on a glass substrate side compared to the color filterand hence, the light blocking films 201 are indicated by dotted lines.The light blocking films 201 are formed of a black resin and contributeto the enhancement of contrast of an image. The light blocking films 201may be made of metal such as Cr.

The light blocking films 201 are formed in a stripe shape in thelongitudinal direction along boundaries of the color filters. Accordingto the present invention, some of the light blocking films 201 is formedin the lateral direction only in regions corresponding to portions ofthe TFT substrate 100 where the TFTs are formed and in regions of theTFT substrate 100 where the drain electrodes 105 are formed. That is, inthis embodiment, there are some light blocking films 201 in the lateraldirection which are not bridged to the light blocking films 201 in thelongitudinal direction. On the other hand, the light blocking films 201having the conventional structure are continuously formed along theboundaries of the pixels in the lateral direction. That is, all of thelight blocking films 201 in the longitudinal direction are bridged toeach other. Due to such constitution, in the present invention, an areain which the light blocking films 201 of the counter substrate 200 areformed is relatively small compared to the conventional liquid crystaldisplay device. Accordingly, in the present invention, it is possible toincrease the brightness by reducing blocking of light from thebacklight.

In FIG. 8, with respect to the green filter G and the blue filter B, thelight blocking films 201 in the lateral direction are not configured tobridge the light blocking films 201 in the longitudinal direction andare cut from each other. In such a portion, the scanning line 1011extends on the TFT substrate 100 and hence, blocking of light from thebacklight is performed by the scanning line 1011. Due to suchconstitution, the transmissivity can be increased.

On the other hand, with respect to the red filter R, the light blockingfilm 201 are bridged to each other. That is, the light blocking films201 in the longitudinal direction are bridged to each other. This isbecause the columnar spacer 202 is formed on the light blocking film 201in the red filter R. The columnar spacer 202 is provided for holding thedistance between the TFT substrate 100 and the counter substrate 200 toa predetermined value. The columnar spacer 202 shown in FIG. 8 has alaterally elongated oblong circle.

To hold the distance between the TFT substrate 100 and the countersubstrate 200 to a fixed value, it is necessary to ensure across-sectional area of the columnar spacer 202 to some extent. Byelongating the columnar spacer 202 in the lateral direction, it ispossible to ensure the cross-sectional area of the columnar spacer 202without increasing a width of the light blocking film 201 in thelongitudinal direction, that is, without reducing the transmissivity.Here, the shape of the columnar spacer 202 is not limited to an oblongcircle and the columnar spacer 202 may be formed into any shape such asan elliptical shape, a rectangular shape as long as being long sideways.

Further, in a boundary portion of two pixels arranged in thelongitudinal direction, that is, in a boundary portion corresponding tothe oblique side of the laterally-extending trapezoidal shape, the lightblocking film 201 is not formed. Due to such constitution, a numericalaperture of the pixel can be further enhanced. Here, two pixels arrangedin the longitudinal direction correspond to color filters having thesame color and hence, there arises no possibility of the occurrence ofcolor mixing.

FIG. 9 shows the arrangement of pixels according to another modificationof the embodiment 1. The constitution which makes the modification shownin FIG. 9 different from the embodiment 1 shown in FIG. 2 lies in thattrapezoidal pixels which are directed in the same direction are arrangedin the lateral direction. On the other hand, in the longitudinaldirection, the pixel electrode 110 shown in FIG. 3 and the pixelelectrode 110 shown in FIG. 6 are alternately arranged thus providingthe packed structure. Accordingly, the constitution shown in FIG. 9 alsoadopts the packed structure in the longitudinal direction as well as inthe lateral direction in the same manner as the constitution shown inFIG. 2.

As shown in FIG. 9, also in this modification, the pixel electrodes 110shown in FIG. 3 and the pixel electrodes 110 shown in FIG. 6 in theembodiment 1 are used and these pixel electrodes 110 are arranged in thepacked structure and hence, this embodiment also can acquireadvantageous effects substantially equal to the advantageous effects ofthe embodiment 1.

It is needless to say that this modification may adopt the pixelelectrodes 110 shown in FIG. 4 or FIG. 5.

The advantageous effects acquired by making the end portions of theslits 112 open-ended in the embodiment 1 are not limited to thetrapezoidal pixels, and such advantageous effects can be also acquiredby applying the present invention to the pixels having a usualrectangular shape.

Embodiment 2

FIG. 10 is a plan view showing the arrangement of pixels of anembodiment 2 of the present invention. FIG. 10 shows the arrangement ofthe pixels, FIG. 11 is an enlarged view of a pixel electrode 110, andFIG. 12 is an enlarged view of an end portion of the pixel electrode110. In FIG. 10, the pixels are defined or partitioned by scanning lines1011 and video signal lines 1041. The pixel electrode 110 has arectangular shape (however, being partially uneven around a throughhole), wherein comb-teeth-shaped electrodes 1101 (slits 112) extend in alongitudinal direction and have distal ends thereof closed. Also in thearrangement of the pixels shown in FIG. 10, the cross-sectionalconstitution of the vicinity of the TFT is substantially equal to thecross-sectional constitution of the vicinity of the TFT in FIG. 1. InFIG. 10, the alignment direction of liquid crystal is a directionindicated by an arrow AL. Here, although the alignment direction ofliquid crystal in the rectangular pixel electrode 110 is slightlyinclined from the long-axis direction in FIG. 10, the alignmentdirection is not limited to such a direction and may be any directionother than the short-axis direction of the pixel electrode 110.

Even when the pixel electrode 110 has such a shape, there is a regionwhere an electric field is directed in an abnormal direction at aportion where a distal end of the comb-teeth-shaped electrode 1101 (slit112) is closed, and an abnormal domain is generated in such a portion.Such an abnormal domain decreases transmissivity. To eliminate thisabnormal domain, in this embodiment, an electrode shape of a distal endportion of the comb-teeth-shaped electrode 1101 has a particular shapeas shown in FIG. 11.

As shown in FIG. 11, a cut-off portion D which is integrally formed withthe slit 112 is formed in a distal end of the comb-teeth-shapedelectrode 1101. Due to such a cut-off portion D, the abnormal domain isstored in the cut-off portion D thus allowing the slit 112 including anend portion except for the cut-off portion D to contribute to a display.A position which overlaps with the pixel electrode 110(comb-teeth-shaped electrode 1101) is originally a position to which anelectric field is hardly formed and hence, even when the abnormal domainis moved to the position, the lowering of transmissivity at such aposition does not occur. Accordingly, the transmissivity is not loweredeven at a distal end of the comb-teeth-shaped electrode 1101 and hence,the transmissivity at the distal end portion of the slit 112 can beenhanced. Here, the slit 112 has both ends thereof closed and hence,this structure can also cope with a pushed domain.

FIG. 12 is an enlarged view of a shape of the distal end portions of thecomb teeth of the pixel electrode 110 shown in FIG. 11. In FIG. 12, acut-off portion D having an inclination is formed in a distal end of thecomb-teeth-shaped electrode 1101. The presence of such a cut-off portionis disadvantageous for the disconnection of the comb-teeth-shapedelectrode 1101. However, assuming that the disconnection occurs in oneportion of the comb-teeth-shaped electrode 1101, according to thisconstitution, the comb teeth is connected with each other at anotherportion, that is, a lower portion of the comb-teeth-shaped electrode1101 shown in FIG. 11 and hence, there is no possibility that a videosignal is not applied to the comb teeth. That is, the cut-off portion Dwhich is integrally formed with the slit 112 is formed in one endportion side of the comb-teeth-shaped electrode 1101, and thecomb-teeth-shaped electrode 1101 at one end portion has a width smallerthan a width of the comb-teeth-shaped electrode 1101 at another endportion. Accordingly, while the portion of the comb-teeth-shapedelectrode 1101 having a narrow width is liable, to be easilydisconnected, the portion of the comb-teeth-shaped electrode 1101opposite to the portion of the comb-teeth-shaped electrode 1101 having anarrow width ensures a large width so that the comb-teeth-shapedelectrode 1101 is hardly disconnected.

Further, assuming that both ends of the comb-teeth-shaped electrode 1101are disconnected, a video signal is not supplied to merely such onedisconnected comb-teeth-shaped electrode 1101 and the whole pixel doesnot become defective. Accordingly, the pixel of this embodiment canmaintain high reliability against the disconnection.

In FIG. 12, with respect to the comb-teeth-shaped electrode 1101, a side(second side in the longitudinal direction) opposite to the side (firstside in the longitudinal direction) where the cut-off portion D isformed with the slit 112 sandwiched therebetween is formed in a straightshape without being bent. That is, as shown in FIG. 12, a portion Fwhich constitutes a corner portion of the slit is formed in aright-angled shape. By forming the portion F in a right-angled shape,the transmissivity of the portion can be enhanced. Due to therelationship with the an alignment axis of the liquid crystal, theenhancement of the transmissivity due to the formation of the cut-offportion D in the comb-teeth-shaped electrode appears in the portion F.

In FIG. 12, no cut-off portion is formed in an outermost portion of thecomb-teeth-shaped electrode 1101 and an inclined portion is formed byincreasing an area of the comb-teeth-shaped electrode 1101. Thisconstitution is provided for decreasing a potential of the disconnectionof the comb-teeth-shaped electrode 1101 at the outermost portion.Although the transmissivity of the pixel at such a portion is decreased,the decrease of the transmissivity appears only in the outermost portionand the vanity of the outermost portion and hence, the influence of theportion on the transmissivity is small.

FIG. 13 is a plan view of the pixel electrode 110 showing a secondmodification of this embodiment. The pixel electrode 110 shown in FIG.13 has a laterally-extending trapezoidal shape, and a profile of thepixel electrode 110 is substantially equal to a profile of thecorresponding pixel electrode 110 shown in FIG. 3. Further, thearrangement of the pixels is substantially equal to the correspondingarrangement of the pixels shown in FIG. 2 and hence, the arrangement ofthe pixels is omitted. That is, also in this embodiment, the pixelsadopt the packed arrangement in the longitudinal direction as well as inthe lateral direction. The technical feature of the arrangement of thepixel electrodes 110 in this embodiment is exactly same as the technicalfeature of the arrangement of the pixel electrodes 110 explained inconjunction with the embodiment 1. Further, an alignment axis of liquidcrystal on a TFT substrate 100 is a direction indicated by symbol AL inFIG. 13. The constitution which makes the pixel electrode 110 shown inFIG. 13 different from the pixel electrode 110 shown in FIG. 3 lies in ashape of the comb-teeth-shaped electrode 1101. Although FIG. 13 showsonly the pixel corresponding to the pixel of the first embodiment shownin FIG. 3, a pixel shape corresponding to the pixel shape shown in FIG.6 appears in symmetry with the pixel shape shown in FIG. 13 and hence,the pixel shape corresponding to the pixel shape shown in FIG. 6 isomitted.

In the pixel constitution shown in FIG. 13, all distal ends of thecomb-teeth-shaped electrodes 1101 (slits 112) are closed by connectionportions. That is, different from the pixel constitution shown in FIG.3, the comb-teeth-shaped electrodes 1101 have no open ends. Thetechnical feature of the pixel constitution shown in FIG. 13 lies inthat, as in the case of the modification 1 of this embodiment, a cut-offportion D having inclination is formed in a distal end of thecomb-teeth-shaped electrode 1101. Due to such a cut-off portion D, theabnormal domain can be stored in the cut-off portion D formed in thedistal end of the comb-teeth-shaped electrode 1101 thus allowing theslit 112 including distal end thereof also to contribute to a display.That is, the transmissivity of the pixel can be enhanced. A cornerportion F of the slit 112 which faces the cut-off portion D shown inFIG. 13 is formed in a right-angled shape. One of the largest technicalfeatures of the present invention lies in the enhancement of thetransmissivity at the corner portion F due to the presence of thecut-off portion D.

This embodiment is characterized in that due to the trapezoidalarrangement of the pixel electrode 110, as explained in conjunction withthe embodiment 1, the area of the light blocking film can be minimizedthus enhancing the transmissivity and, at the same time, reducing thedirectivity of a viewing angle. In addition to these advantageouseffects, an abnormal domain generated in the distal end of thecomb-teeth-shaped electrode 1101 (slit 112) is moved to the inside ofthe cut-off portion D thus enhancing the transmissivity of the pixel.

In the above-mentioned embodiment, the cut-off portion D is formed inboth ends of the comb-teeth-shaped electrode 1101. When the cut-offportion D is formed in both ends of the comb-teeth-shaped electrode1101, a possibility of occurrence of the disconnection in thecomb-teeth-shaped electrode 1101 is increased. To further reduce thepossibility of occurrence of the disconnection, as shown in FIG. 14, thecut-off portion D may not be formed in one side of the comb-teeth-shapedelectrode 1101 and the cut-off portion D may be formed only in anotherside of the comb-teeth-shaped electrode 1101. Due to such constitution,a transmissivity enhancing effect is halved compared to the case shownin FIG. 13. However, the possibility of occurrence of the disconnectionof the comb-teeth-shaped electrode 1101 is largely decreased. That is,although the possibility of the disconnection of the comb-teeth-shapedelectrode 1101 exists on both sides of the comb-teeth-shaped electrode1101 in the pixel constitution shown in FIG. 13, the possibility of thedisconnection on side of the comb-teeth-shaped electrode 1101 isextremely small in the pixel constitution shown in FIG. 14 and hence,the probability that the whole comb-teeth-shaped electrode 1101 suffersfrom the insufficient electrical conduction becomes extremely small. Inthe pixel electrode 110 shown in FIG. 15, non-cut-off portions areformed on a side of the comb-teeth-shaped electrode 1101 opposite to theside of the pixel electrode 110 shown in FIG. 14 on which thenon-cut-off portions are formed. This pixel electrode 110 shown in FIG.15 also can acquire the substantially same advantageous effect as thepixel electrode 110 shown in FIG. 14.

Embodiment 3

FIG. 16 is a plan view of the pixel electrode 110 showing a thirdembodiment of the present invention. The pixel electrode 110 shown inFIG. 16 has a laterally-extending trapezoidal shape, and a profile ofthe pixel electrode 110 is substantially equal to a profile of thecorresponding pixel electrode 110 shown in FIG. 3. Further, thearrangement of the pixels is substantially equal to the correspondingarrangement of the pixels shown in FIG. 2 and hence, the arrangement ofthe pixels is omitted. That is, also in this embodiment, the pixelsadopt the packed arrangement in the longitudinal direction as well as inthe lateral direction. Although FIG. 16 shows only the pixelcorresponding to the pixel of the first embodiment shown in FIG. 3, apixel shape corresponding to the pixel shape shown in FIG. 6 appears insymmetry with the pixel shape shown in FIG. 16 and hence, the pixelshape corresponding to the pixel shape shown in FIG. 6 is omitted. Thetechnical feature of the arrangement of the pixel electrodes 110 in thisembodiment is exactly same as the technical feature of the arrangementof the pixel electrodes 110 explained in conjunction with theembodiment 1. Further, an alignment axis of liquid crystal on a TFTsubstrate 100 is a direction indicated by symbol AL in FIG. 16.

Also in the pixel electrode 110 shown in FIG. 16, in the same manner asthe pixel electrode 110 shown in FIG. 3, the slits 112 of the pixelelectrode 110 have end portions thereof opened for every one other slit(at a rate of one slit for every two slits). That is, the slit 112having both ends thereof closed and the slit 112 having only one-sideend portion thereof opened are alternately arranged next to each otherin parallel. However, the opened end portions of the slits 112 areformed alternately on different sides of the trapezoidal pixel electrode110. Accordingly, within one pixel electrode 110, all comb-teeth-shapedelectrodes 1101 are made conductive with each other. In a portion wherea distal end is opened, there is no possibility that an abnormal domainis formed. Accordingly, the transmissivity of the pixel can be enhancedcorrespondingly. That is, the pixel electrode 110 shown in FIG. 16 alsoacquires the advantageous effect of the pixel electrode 110 of theembodiment 1.

The constitution which makes the pixel electrode 110 shown in FIG. 16different from the pixel electrode 110 shown in FIG. 3 lies in thatcut-off portions D are formed in a closed distal end portion of thepixel electrode 110. Advantageous effects obtained by the cut-offportions D are exactly as same as the advantageous effects explained inconjunction with the embodiment 2. That is, this embodiment possessesboth of the advantageous effects acquired by the embodiment 1 and theadvantageous effects acquired by the embodiment 2. In this manner, thisembodiment can further enhance the transmissivity of the liquid crystaldisplay device than the embodiment 1 and the embodiment 2.

Although the pixel electrode 110 shown in FIG. 16 can enhance thetransmissivity, the possibility of the disconnection of thecomb-teeth-shaped electrode 1101 is larger than the possibility of thedisconnection of the comb-teeth-shaped electrode 1101 in theembodiment 1. To cope with the disconnection of the comb-teeth-shapedelectrode 1101 of the pixel electrode 110 shown in FIG. 16, in the samemanner as the pixel electrode 110 shown in FIG. 14 or FIG. 15 explainedin conjunction with the embodiment 2, the cut-off portion D may beformed in only one side of the comb-teeth-shaped electrode 1101.

Further, the pixel structure shown in FIG. 16 may be combined with thepixel structure explained in conjunction with FIG. 4 or FIG. 5.

In the above-mentioned embodiment, the explanation has been made byassuming that the pixel arrangement shown in FIG. 16 is equal to thepixel arrangement shown in FIG. 2. However, the pixel arrangement shownin FIG. 16 may be equal to the pixel arrangement shown in FIG. 9.Alternatively, a profile of the pixel may be a rectangular shape or thepixel arrangement shown in FIG. 10 may be adopted.

1. A liquid crystal display device comprising: a TFT substrate; acounter substrate; and liquid crystal which is sandwiched between theTFT substrate and the counter substrate, wherein the TFT substrateincludes planar first electrodes, an insulation film which covers thefirst electrodes, and second electrodes which are formed on theinsulation film in an overlapping manner with the first electrodes, thesecond electrode includes slits and comb-teeth-shaped electrodes, theliquid crystal is configured to be driven by an electric field generateddue to potential difference between the first electrode and the secondelectrode, and the slits are configured such that the slits having bothends thereof closed and the slits having only one-side end portionthereof opened are alternately arranged next to each other in parallel.2. A liquid crystal display device according to claim 1, wherein withinone pixel, the slits having only one-side end portions thereof openedare configured such that the slit opened on one end portion side and theslit opened on another end portion side are arranged alternately by wayof the slit having both end portions thereof closed.
 3. A liquid crystaldisplay device according to claim 1, wherein within one pixel, the slitshaving said only one-side end portions thereof opened include the slitsopened on one end portion side and the slits opened on another endportion side.
 4. A liquid crystal display device according to claim 1,wherein within one pixel, the slits having said only one-side endportions thereof opened are opened only on the same one end portion siderespectively.
 5. A liquid crystal display device comprising: a TFTsubstrate; a counter substrate; and liquid crystal which is sandwichedbetween the TFT substrate and the counter substrate, wherein the TFTsubstrate includes planar first electrodes, an insulation film whichcovers the first electrodes, and second electrodes which are formed onthe insulation film in an overlapping manner with the first electrodes,the second electrode includes slits and comb-teeth-shaped electrodes,the liquid crystal is configured to be driven by an electric fieldgenerated due to potential difference between the first electrode andthe second electrode, and the comb-teeth-shaped electrode is configuredsuch that a cut-off portion which is integrally formed with the slit isformed in one end portion side of comb-teeth-shaped electrode, and saidone end portion side of the comb-teeth-shaped electrode has a widthsmaller than a width of another end portion side of thecomb-teeth-shaped electrode.
 6. A liquid crystal display deviceaccording to claim 5, wherein the slits are configured such that theslits having both ends thereof closed and the slits having only one-sideend portions thereof opened are alternately arranged next to each otherin parallel.
 7. A liquid crystal display device comprising: a TFTsubstrate; a counter substrate; and liquid crystal which is sandwichedbetween the TFT substrate and the counter substrate, wherein the TFTsubstrate includes planar first electrodes, an insulation film whichcovers the first electrodes, and second electrodes which are formed onthe insulation film in an overlapping manner with the first electrode,the second electrode includes slits and comb-teeth-shaped electrodes,the liquid crystal is configured to be driven by an electric fieldgenerated due to potential difference between the first electrode andthe second electrode, and the comb-teeth-shaped electrode includes afirst side and a second side which respectively extend in a longitudinaldirection and face each other in an opposed manner with the slitsandwiched therebetween, a cut-off portion which is integrally formedwith the slit is formed only in one side out of the first side and thesecond side on at least one end portion of the comb-teeth-shapedelectrode, and another side out of the first side and the second side isformed in a straight line without being bent.
 8. A liquid crystaldisplay device according to claim 7, wherein the cut-off portion whichis integrally formed with the slit only on one side is formed in bothend portions of the comb-teeth-shaped electrode.
 9. A liquid crystaldisplay device according to claim 7, wherein the cut-off portion whichis integrally formed with the slit only on one side is formed in onlyone end portion of the comb-teeth-shaped electrode.